1. Field of the Invention
The present invention relates to a blood vessel coagulation/stanching device used to stop bleeding from blood vessels during cerebral nerve surgery, orthopedic surgery and general surgery operations.
2. Prior Art
A conventional bipolar-type blood vessel coagulation/stanching device uses high-frequency current. A number of such conventional devices employing a spark gap method generating high frequency ranging between 0.5 to 3 MHz have been used. The two electrodes (active and inactive electrodes) of the bipolar type device are provided at both ends of a pair of forceps to be held by hand. Electric current flows only through the living tissue held between the ends of the forceps. Since electric damage to a patient is applied only to a limited portion to be coagulated, bleeding from a blood vessel can be stopped completely without injuring other tissues. More specifically, the stanching effect of the device is obtained by coagulating the blood vessel using localized heating caused by the high-frequency current flowing through the living tissue.
However, stainless steel is mostly used as the material of the conventional forceps. Titanium which is light and corrosion resistant is also used these days. Since these forceps made of metal are high in thermal conductivity, they tend to conduct heat easily. Due to this tendency, the heat of a locally heated blood vessel is reversely transferred to the metal forceps. As the pair of forceps is used, the temperature at the front end portions of the forceps gradually rises. This causes burning between the ends of the metal forceps and the blood vessel. As a result, a part of the blood vessel attaches to the ends of the forceps. This attaching force is greater than the coagulation force of the blood vessel. When the ends of the forceps are separated from each other after the blood vessel is coagulated, the coagulation portion of the blood vessel is often separated and removed. This causes the blood vessel to tear and results in failure in stopping bleeding. In addition, the burnt substance attached to the ends (electrodes) of the forceps must be shaved off and cleaned for the subsequent use. This shaving and grinding work causes inexpedient problems: change in the shapes of the ends of the forceps and the reduction in the accuracy of the forceps.